Field
Embodiments described herein generally relate to semiconductor manufacturing and more particularly to a method and apparatus for providing process gases for processing a semiconductor substrate.
Description of the Related Art
During the manufacture of semiconductor devices, a substrate may undergo multiple operations in a variety of processing chambers, or even a single processing chamber, for the purpose of forming material layers and features suitable for an end use. For example, the substrate may undergo several depositions, annealing, and etching operations, among other operations.
Device miniaturization has made small dimensions for device patterns formed in a film layer of the substrate more critical. Achieving the critical dimensions in the substrate begins with a good quality film layer having good adhesion to the underlying film layers in the substrate. Forming vias and other high quality closely packed features in the substrate may require processes utilizing multiple gases during a single operation. For example, the formation of deep vias may require precise control of process gas flows into the processing chamber for etching as well as forming protective polymerization layers for ensuring the deep vias have substantially vertical sidewalls. Maintaining good control for the delivery of the process gases during processing promotes process uniformity in forming the quality device features.
Gas delivery systems used with semiconductor processing chambers generally include either a mass gas flow meter (MFC) as the primary flow regulation device or a system of fast valves for fast gas exchange. Gas delivery systems with fast evacuation paths enable a plurality of processing gases to be supplied from the gas delivery systems into the processing system with a stable gas flow and minimum fluctuation. The fast gas exchange systems use a plurality of orifices, or choke points, to tune the flow paths for controlling the flow of the different process gases. However, the fast gas exchange systems are a complicated system of orifices and valves which take up considerable real estate and are costly to implement and maintain.
Therefore, there is a need for a low cost and effective gas delivery system for controlling the delivery of process gases to a processing system.